The present invention relates generally to a stent assembly for use during a surgical procedure. In particular, the present invention is directed to a temporary stent assembly for temporarily securing a surgical component during a surgical procedure during the process of permanently securing the surgical component to a vessel.
An aneurysm is a ballooning of the wall of an artery resulting from the weakening of the artery due to disease or other conditions. Left untreated, the aneurysm will frequently rupture, resulting in loss of blood through the rupture and death.
Aortic aneurysms are the most common form of arterial aneurysm and are life threatening. The aorta is the main artery which supplies blood to the circulatory system. The aorta arises from the left ventricle of the heart, passes upward and bends over behind the heart, and passes down through the thorax and abdomen. Among other arterial vessels branching off the aorta along its path, the abdominal aorta supplies two side vessels to the kidneys, the renal arteries. Below the level of the renal arteries, the abdominal aorta continues to about the level of the fourth lumbar vertebrae (or the navel), where it divides into the iliac arteries. The iliac arteries, in turn, supply blood to the lower extremities and perineal region.
It is common for an aortic aneurysm to occur in that portion of the abdominal aorta between the renal arteries and the iliac arteries. This portion of the abdominal aorta is particularly susceptible to weakening, resulting in an aortic aneurysm. Such an aneurysm is often located near the iliac arteries. An aortic aneurysm larger than about 5 cm in diameter in this section of the aorta is ominous. Left untreated, the aneurysm may rupture, resulting in rapid, and usually fatal, hemorrhaging. Typically, a surgical procedure is not performed on aneurysms smaller than 5 cm as no statistical benefit exists to do so.
Aneurysms in the abdominal aorta are associated with a particularly high mortality rate; accordingly, current medical standards call for urgent operative repair. Abdominal surgery, however, results in substantial stress to the body. Although the mortality rate for an aortic aneurysm is extremely high, there is also considerable mortality and morbidity associated with open surgical intervention to repair an aortic aneurysm. This intervention involves penetrating the abdominal wall to the location of the aneurysm to reinforce or replace the diseased section of the abdominal wall (i.e., abdominal aorta). A prosthetic device, typically a synthetic tube graft, is used for this purpose. The graft serves to exclude the aneurysm from the circulatory system, thus relieving pressure and stress on the weakened section of the aorta at the aneurysm.
Repair of an aortic aneurysm by surgical means is a major operative procedure. Substantial morbidity accompanies the procedure, resulting in a protracted recovery period. Further, the procedure entails a substantial risk of mortality. While surgical intervention may be indicated and the surgery carries attendant risk, certain patients may not be able to tolerate the stress of intra-abdominal surgery. It is, therefore, desirable to reduce the mortality and morbidity associated with intra-abdominal surgical intervention.
In recent years, methods have been developed to attempt to treat an abdominal aortic aneurysm without the attendant risks of intra-abdominal surgical intervention. Although techniques have been developed that may reduce the stress, morbidity, and risk of mortality associated with surgical intervention to repair aortic aneurysms, none of the prior art systems that have been developed effectively treat the aneurysm and exclude the affected section of aorta from the pressures and stresses associated with circulation. None of the devices disclosed in the references provide a reliable and quick means to reinforce an aneurysmal artery. In addition, all of the prior references require a sufficiently large section of healthy aorta abutting the aneurysm to ensure attachment of the graft. The proximal aortic neck (i.e., above the aneurysm) is usually sufficient to support a graft""s attachment means. However, when an aneurysm is located near the iliac arteries, there may be an ill-defined neck or no neck below the aneurysm. Such an ill-defined neck would have an insufficient amount of healthy aortic tissue to which to successfully attach a graft. Furthermore, much of the abdominal aortic wall may be calcified making it extremely difficult to attach a graft thereto.
There are a number of shortcomings with the presently available graft products and their fixation within the abdominal aorta. Although sizing of xe2x80x9ctubexe2x80x9d or xe2x80x9cbifurcatedxe2x80x9d grafts is radiographically assessed prior to surgery, it is necessary for the surgeon to have a large selection of graft lengths and diameters on hand to ensure an appropriate surgical outcome. Additional shortcomings include the placement of a xe2x80x9ccircularxe2x80x9d profile graft with an associated fixation device within an essentially xe2x80x9covoidxe2x80x9d profiled vessel and the use of attachment means which fasten only to the insubstantial, structurally compromised (diseased) intima and media layers (i.e., strata) of the vessel wall. Research has shown yet another problem which indicates that the necks of the post-surgical aorta increase in size for approximately twelve months, regardless of whether the aneurysm experiences dimensional change. This phenomenon can result in perigraft leaks and graft migration.
Graft migration is a significant problem affecting many of the grafts available within the intraluminal abdominal aortic aneurysm market. These grafts are attached within the aortic lumen at a proximal positioning by means of stents, which provide outward radial forces thereby forcing the graft into the lumen wall. In some instances barbs, part of the stent fabrication, provide additional fixation. There are numerous problems with this design approach. The stent of the aforementioned concept is expanded into a compromised vessel having questionable mechanical integrity. Second, the proximal distal neck has been shown to expand immediately post operatively and for a period of twelve months thereafter causing the graft to detach from or loosen with respect to the lumen. Finally, the barbs of the stent product are of questionable merit as they fasten into the intima of the lumen wall which has compromised mechanical integrity.
By comparison, the present inventors developed a graft assembly disclosed in U.S. patent application Ser. No. 08/896,415, filed Jul. 18, 1997, entitled xe2x80x9cMethod and Apparatus for the Surgical Repair of Aneurysms,xe2x80x9d the disclosure of which is incorporated herein by reference, that is positively fastened to the adventia, the outermost of three strata within the vessel wall, having appropriate mechanical integrity. The grafts disclosed in U.S. patent application Ser. No. 08/896,415 are not comprised by expansion of the distal neck. The present invention addresses the short comings of the prior art grafts. The present invention also enhances the performance of the graft assembly disclosed in U.S. patent application Ser. No. 08/896,415.
It is an object of the present invention to provide a temporary stent assembly for use during a surgical procedure.
It is another object of the present invention to provide a temporary stent assembly that can be selectively positioned within a vessel to temporarily secure a surgical component in place during a surgical procedure.
It is another object of the present invention to provide a stent assembly for use in a surgical procedure that can be advanced through a vessel and extended to secure a surgical component in place while the surgical component is being permanently secured to a vessel wall.
It is another object of the present invention to provide a stent assembly that is capable of holding a graft assembly against the aortic neck such that the graft assembly can be fastened to avoid leakage.
The present invention is directed to a stent assembly for use in temporarily securing a surgical component during a surgical procedure. The stent assembly includes a catheter assembly having at least one primary passageway extending there through. The stent assembly further includes a securing assembly defining a surface for exerting a force against an inner surface of the surgical component for temporarily securing the surgical component during the surgical procedure. The securing assembly includes a portion that extends through the at least one primary passageway. The catheter assembly may include a secondary passageway. The secondary passageway is adapted to receive a guide device therein. The securing assembly has a retracted position and an extended position. The securing assembly exerts a force against the surgical component while the securing means is in the extended position. The securing assembly may contain a coating which increases the gripping force of the securing assembly.
The stent assembly may be advanced through a vessel in order to selectively position the stent assembly with the securing assembly in the retracted position. The stent assembly may be inserted into the vessel via an axillary incision, a brachial incision, or a femoral or a common iliac arteriotomy, and may be used in the repair of an aneurysm.
According to an embodiment of the present invention, the stent assembly may be used to hold a surgical component against a vessel wall, wherein the surgical component may be fastened to the vessel wall to avoid leakage.
According to an embodiment of the present invention, the stent assembly may comprise a catheter assembly having a first primary passageway and a second primary passageway extending there through and a securing means for exerting a force against the surgical component for temporarily securing the surgical component during the surgical procedure, wherein the securing means includes a portion that extends through the first primary passageway and the second primary passageway. The first primary pasasgeway and the second primary passageway may be located adjacent to one another.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only, and are not restrictive of the invention, as claimed. The accompanying drawings, which are incorporated herein by reference, and which constitute a part of this specification, illustrate certain embodiments of the invention, and together with the detailed description serve to explain the principles of the present invention.